Kinetic investigation of the collisional behavior of ground state atomic carbon, C(2p2(3PJ)), with halogenated olefins and aromatic compounds studied by time‐resolved atomic resonance absorption spectroscopy in the vacuum ultra‐violet

Abstract

AbstractA kinetic investigation is described of the reaction of ground state atomic carbon, C(2p2(3PJ)), monitored by time‐resolved atomic resonance absorption spectroscopy, with a wide range of halogenated olefins and aromatic compounds. Atomic carbon was generated by the repetitive pulsed irradiation (λ > ca. 160 nm) of C3O2 in the presence of excess helium buffer gas and the added reactant gases in a slow flow system, kinetically equivalent to a static system. C(23PJ) was then monitored photoelectrically by time‐resolved atomic resonance absorption in the vacuum ultra‐violet (λ = 166 nm, 33PJ ← 23PJ) with direct computer interfacing for data capture and analysis. The following absolute second‐order rate constants for the reactions of C(23PJ) with the following reactants are reported: Reactant kR/cm3 molecule−1 s−1 (300 K) C2F4 (1.9 ± 0.1) × 10−10 C2Cl4 (10.6 ± 0.5) × 10−10 CH2CF2 (4.3 ± 0.2) × 10−10 CHClCCl2 (7.9 ± 0.4) × 10−10 C6H6 (4.8 ± 0.3) × 10−10 C6F6 (4.9 ± 0.3) × 10−10 C6HF5 (5.0 ± 0.3) × 10−10 C6H2F4 (4.4 ± 0.2) × 10−10 C6H5—CH3 (5.5 ± 0.3) × 10−10 C6F5—CF3 (5.4 ± 0.3) × 10−10 These results, constituting the first reported body of absolute rate data for reactions of ground state carbon with these reactants, are compared with the analogous body of absolute rate data for atomic silicon in its Si(3p2(3PJ)) ground state, also determined hitherto by time‐resolved atomic resonance absorption spectroscopy and demonstrating similar kinetic behavior. © 1993 John Wiley & Sons, Inc.